Electrical measuring instrument



Jufiy 24- 193 H @EHGER L97fi1 ELECTRICAL MEASURING INSTRUMENT Filed Nov. 7, 1933 WIT/V5555? INVENTOR. yo wu Q QQ Patented July 24, 1934 1,967,710 ELECTRICAL MEASURING IusTRUMENT Wesley H. Geiger, Wormleysburg, Pa. Application November -7, 1933, Serial No. 696,952

Claims.

My invention relates to electrical measuring instruments, more especially to a combined alternating current volt and polarity meter,

One object of my invention is to combine with an alternating current voltmeter a secondary or testing circuit to beused in checking the polarity with the circuit of the voltmeter.

Another object, of my invention is to make one instrument that can be used as a voltmeter and also as a polarity meter or in other words combining the two instruments in one. without deviating from the general construction of the varied types of meters.

Fig. 1 represents one embodiment of my combined voltmeter and polarity indicator,

Fig. 2 is a modification thereof.

A meter of this kind consists of an addition o an extra magnetizing coil wound over or in inductive relation to the voltmeter actuating current so as to coact or react on said meter indications so that an increased strength in the voltmeter field would show an increase on the meter scale. This would mean that the polarities of the two circuits would be the same as the marks on the connecting binding post and a decreased strength of this field would show a decrease on the voltmeter scale and would indicate that the polarity in the second or testin circuit was unlike that of the first circuit. An instrumerit of this kind would be very useful in railway signaling work, and especially where polyphase apparatus is used, such as polyphase relays in alternating current signaling.

Construction Figure 1 represents'an alternating current voltmeter of the type having a lamihated electromagnet 1-, a movable coil 2, pivoted at 3, a spring 4 to hold the coil in position and a pointer 5, indicating on the scale 6L .Upon this electromagnet 1, is wound the potential coil 40 or primary winding 7, actuating the voltmeter connected to the positive terminal post 8, by wire 9. The other end-of this coil is connected to the wire 10 through the movable coil 2 wire 11, to terminal post 112 which represents the one volt terminal of the instrument. ix, 2a: and 3x are resistances connecting the 5, 25, and 125 volt scales on the meter, as is done in common practice. The coil 7a is inductively wound over or in same magnetic field as the coil 7. One end of this coil 70. is connected by wire 9a to the rheostat compri ing he parts R1; R2, 3 and R4. This rheostat is used to compensate fordifierent voltages of this circuit and has the co,ntact arm Rlheld in the oft contact position by the spri g R2 against the stop R3, the winding of this rheostat R4 is connectedtoterminal 18a. The other end a of this coil is connected throu h the fuse 10a to the terminal 81).

Construction Figure 2 represents an alternating currentvoltmeter of a different type, having source of the same current.

. voltmeter.

source. "wire 9?), primary or potential magnetizing coil 7b, wire lobfto lob, wire 1.32:0, wire Zxm'to the 25 a fixed vane 1i), paralleling the magnetic field of I the instrument. 212 is a movable vane parallel with the fixed vane 11). Vane 21) is attached'to the po t r 5b, pivo ed t 3b, indicat ng on the scale 6a. The primary coil 7b is the voltmeter ma n z n or primary coil connec d by the wire 9b to the bindin p t 86. Th oth d of this primary coil is connected by 101) to the post lvb, 5121), 2512b and 125%, which are connected and used as in Figure l by the resistance wires 1m, 2m: and 3900:. The secondary or polarity test coil is used in inductive relation to the current in the coil lb'of the voltmeter, The external connections of this 'coil are similar to the coil 7c in Figure 1.

Operation Figure 1 illustrates a source of a1- ternating current connected to the terminal 8 and the terminal 251) is connected to the other This will cause current to flow from post 8, wire 9, throu h the primary magnetizing coil '7, wire 10, to the movable coil 2, wire 11 to post 11), 1x, 2x, to the 2512 terminal, causing the pointer 5 to move to the 25 volt point on the scale, which is the voltage of this current. We will now assume that we have another or secondary source of current that we wish to determine the polarity of, in relation to the current going through the We will connect this source to be tested or checked to the terminal 8a and th other'side of thiscircuit to the terminal 81;. The rheostat arm R], is then moved to connect with the BA resistance until the pointer 5 shows an increase or decrease on the 25 volt point on scale which was the indicated voltage of the primary current. If this reading shows an in .crease on this scale it will indicate that the rent connected to the terminal 8e and the terminal25ob is connected to the other wire of same This will cause current to flow through volt terminal; This will magnetize the vanes 11) and 22). As like magnetic poles repel this will jcause the two vanes t r bel an ov the poin er 5?) to the..25 volt division on scale which is the voltage of the first source of current. We will now connect another source to determine the polarity, connecting one wire to terminal and I the other wire of this circuitto be checked to the p st 8dsin his is the same as n g r It is to be understood that I do not limit this invention to the types of meters shown in the drawing as it may have other uses without departing from the novelty of the invention.

I claim:

1. In combination with an alternating current voltmeter, having a primary winding and a source or" current, of a secondary test circuit inductively related to said primary, circuit.

2. In combination with an alternating current voltmeter, having a primary or operating circuit as used in measuring alternating current voltages, of a secondary test circuit inductively related to said primary or operating circuit.

3. In combination with an alternating current voltmeter, having a primary winding to operate said voltmeter, of a secondary winding inductively related to said primary winding'to determine the relation of said circuit in the secondary winding.

4. In combination with an alternating current measuring instrument having a primary winding and a source of current for said instrument, of a secondary winding inductively connected to said primary winding, and a source of current for said secondary winding and means to determine the relation of said secondary current in relation to the first or primary current. 5. In combination with an alternating current voltmeter a source of current and a potential coil to operate said meter, of a secondary Winding inductively related to said potential coil and a source of current for said secondary winding and means whereby said meter will in one direction indicate a like polarity and a movement of said meter in the opposite direction will indicate an unlike polarity of the circuit being tested. 7

6. In combination with an alternating current measuringinstrument, a primary coil, a magnetic field produced by said primary coil and a movable element actuated by said primary coil when connected to'a source of current, of a secondary coil inductively related to said primary coil and magnetic field, so as to vary the strength of said magnetic field when the secondary coil is connected to a second source of current thereby indicating by the movable element the relation of the current in said secondary coil' to that of the first'source or" current.

'7. In combination With an alternating current voltmeter and a source of current for said meter, of a second source of current to be tested inductively connected to said first source of current in such a manner as to cause an increase or decrease of the flux produced by said first source of current through said voltmeter.

8.' In combination with an alternating current measuring'instrument and a source of current for said instrument of a second testing current inductively associated with the first said current to increase or decrease the effect produced upon said measuring instrument when the two sources of current are connected to their respective instrument windings. V

9. In combination with an alternating current measuring instrument .and a source of current for said instrument, of a second source of current inductively related to said first source and means to determine the relation of the second source of current by the inductive efie'ct on first said current as indicated by said measuring instrument.

10. In a combined alternating current volt current.

and indicate the voltage of said source of ourof current.

and polarity meter, the combination with an alternating current voltmeter having a primary winding and a source of current ior said winding and adapted when energized to indicate the voltage of said current,'of a second or polarity test circuit inductively related to said primary circuit to vary the indicated voltage on said meter when said secondary circuit is connected to the second source of current.

11. In a combined Volt and polarity meter, the combination with an alternating current voltmeter of a first and a second source of current, said meter when connected to the first source of current indicating the voltage of the circuit connected to the voltmeter, the .second source of current being inductively associated with the first source of current and adapted to coact or react with said first source of current to vary the indicated voltage of said first source of current, thereby indicating the polarity of the second source in relation to that of said first source of current.

12. In a combined alternating current volt and polarity meter, the combination with two sources of current having like or unlike polarities, an alternating current voltmeter adapted to be connected to one of said sources of current to in dicate the voltage of said circuit, means inductively associated with said alternating current voltmeter and the other source of current to coact or react on the indicated Voltage on said meter and said first source of current to determine the polarity'of the other source of current in relation to that of the first source of 13. In a combined alternating current volt and polarity meter, the combination with an alternating current voltmeter, asource of current and a voltage coil to operate said meter rent, means when connected to said first source of current to indicate the intensity of said source and means inductively associated with the second source of current to vary the intensity of the first source of current as indicated by said measuring instrument to determine the condition of said second source in relation to that of the first source. I I

15. In an alternating current measuring instrument, the combination with an alternating current measuring instrument, a first and a second source of current, a primary coil and a magnetic field produced by said primary coil when connected to the first source of current and a movable element actuated by said primary coil and magnetic field to indicate the intensity of the first source of current, of means induc tively associated when connected toi the second source of current to change the strength of-the magnetic field energized by the first "source of current thereby varying the indicated intensity of the first source of current by said movable element in relation to that of the second source WESLEY H. GEIGER, 

